What changed Washington’s mind? In part, it was an urgent and confidential back-channel initiative involving former European leaders and senior officials, and ultimately endorsed by the Chinese. Ever since Putin’s 27 February declaration on nuclear readiness, the PLA had also been reaching out through military-to-military (as opposed to diplomatic or political) channels to senior Russian general officers with whom they had made personal contact over years of joint military exercises and military procurement talks. Beijing’s aim was to ensure that even if there were a political decision to use nukes, the Russian army would insist on sticking to its long-standing nuclear military doctrine to use them solely if provoked by attacks on Russian soil. Through these unofficial ‘track two’ contacts, Washington and the PLA agreed – unusually, given a deterioration in relations during the Donald Trump presidency – that if the US stopped the MiG deal, Beijing’s generals would do their best to defuse Putin’s nuclear threat on an operational level. ‘It worked,’ said the Chinese source. ‘The [US] decided that supplying aircraft was a step too far.’